Trimming the FD

TRIMMING AN FD

As published in the Dutch FD Newsletter, and then in the International Bulletin a few years ago. The English version has Cle Jeltes imprint on it, but I felt it was best left as it was translated, firstly, its better than anything I could write in Dutch, and secondly, we are a real international class after all.

GENERAL

Since racing started in FDs sailors have speed problems. Incidental or structural. After each race you will hear “all of a sudden my speed disappeared”. For some speed is something magical, for some accidental but for the ones sailing upfront rational. Thinking and acting along the correct steps, together with the feeling (gained through training) will produce speed. Training is your own problem but may be we can help with the trim.

The FD is a fast boat where specially with a lot of wind big speed differences can occur. The trick of trimming is the accurate react-ing on wind changes so that the FD can be sailed at an optimum at all times. She must keep running and not stop.

This article is meant primarily for novice FD sailors and recreational sailors who want to have some more control over their boat. Of course the more advanced are allowed to have a peep in the kitchen of the competition.

DEVELOPMENTS

Since the early eighties one development has been of extreme importance:

The so called RAKE, which is of great influence on speed and control. It has been discovered more or less at the 1983 Worlds in Australia. A not so well known Kiwi appeared to be, with much wind, a lot faster than the favourites. Noticeable was that his mast was leaning extremely backwards. This lead to many putting on a thinking cap and experimenting, with LA 84 in the back of their minds. A period with much experimenting followed.

Sails. CB position, masts, shroud positions, everything was reconsidered. Now the situation has stabilised again and boats and material are pretty identical.

With not too ancient equipment and a good trim much speed can be obtained in an FD.

TRIMMING

Do not try to reinvent the wheel. Use those who know how to go fast. Most are willing to explain and answer questions. The FD Class has the luxury that at all European and World Championships statistics of used equipment are produced. Use them. Those materials have proved themselves and can be made to go fast. Experimenting takes an enormous amount of time and works really only for very experienced FD sailors who will actually notice the differences.

FIGURES AND REFERENCE POINTS

When you want to refit an old boat or build your own boat it is important to have some dimensions which are free but of great influence on trim. They constitute the basis on which to start trimming. So before you start fitting out the boat you better go to an FD event with note pad and ruler and write down the various positions of fittings and take-off points. –

The most important are:

Shroud position: 3.25 m from transom,0.60 m from centreline

Lower shrouds : on mast – just above black band for the boom

in the boat – ust aft of the shrouds

Spreaders: 40-45 cm long, pushing shrouds approx 10cm outward,

85-90cm between ends. Height about halfway between deck and jib halyard. Fine adjustment depends on type of mast, sails and crew weight

POSSIBILITIES

1. Shrouds

They regulate, together with the genoa-halyard, the rake. A 20cm adjustment is required. Reduction 1:24. Be sure to have the adjustment synchronous on both shrouds. Most common is a 3-sheave block on the shrouds, a double two-sheave on the anchorage in the boat and along the CB case a two-sheave with becket, adjustable on both sides. With little wind the mast will be sailed leaning slightly forward, and raking much aft with a lot of wind. Mast top moves about 1.5 m!! With very light winds the lee shroud can be loose, tightening with increasing wind to maximum with a blow.

2. Lower shrouds

Indispensable trimming item for mast and pressure control. Reduction 1:12 is adequate. Gives control on belly of the main and gap between genoa and main.

With very light winds loose, then tightened to the keep mast stiff till excessive pressure has to be released. Always check the mastbend from the trapeze before the start.

3. Genoa-halyard

Directly connected with shroud adjustment. Necessary reduction approx 1:18 with appropriate adjustment length (Coarse and fine adjustment is advisable). With little wind it must be possible to pull mast forward whilst with much wind the mast must be able to drop backwards. Adjust tension so that with little wind there is some sagging and with much wind there is enough to point. With real much wind the halyard can let go a little to get rid of some pressure.

4. Fairleads.

After a period with fixed fairleads now adjustable ones are most common. Maximum adjustment allowed is 6 cm below and 6 cm above deck, measured from top of deck to centre of sheave. The aft position is limited through a black band on deck. Athwartships no limitation. With little wind the fairleads are above deck, with increasing wind they are to disappear under the deck. Watch the gap between main and genoa. A good reference point is the distance be-tween genoa and spreader end. With very little wind approx 30 cm. some more wind 10 cm and then when pressure has to be got rid off opening up to max 50 cm. Adjustment up-down and out-in should be synchronous operational on both tacks.

5. Kicking strap

Reduction 1:12 is sufficient. Do not apply too much tension, certainly not with light winds. Important for main leech control. Make sure that with much wind in reaches the kicker is rather loose as it gives much better control on these rides. The superfluous pressure can be more easily dumped from the main and the boom is less likely to hit the water (which would be end of exer-cise)

6.Traveller

Very fancy and very expensive is the Har-ken windward sheeting traveller. Can be pulled to windward without having to re-lease the leeward side. It is preferable over other systems: in practice it proves to give better mainsail control. Also with more wind the traveller will be put a little bit to windward to obtain proper twist in the main.

7. Cunningham hole

Usually operational on both sides. Good control of mainsail belly. Tightening moves the belly forward whilst wind pressure tends to move belly aft.

8. Mainsail outhaul

A reduction of 1:4 and a clamcleat on the boom near the mast works well.

9. Centreboard

Also an important trim item. With little wind maximum down and forward. When the wind increases move aft and up. Make sure the CB has no play in the case. Forward and aft adjustment with reductions is most stylish.

10. Mastbend adjustment

A trick used recently is to have a small piece of line round the mast to produce pre-bend. Only used with little wind to bend the mast without tension on the sail so the leech can be opened up.

11. Geriatric’s rope.

Not everybody uses it. About 20 cm above the main clew eyelet a second eyelet is fitted with a line running forward along the boom. With extreme rake the boom will almost hit the deck and taking in on this line will pull up the boom. The main under these condi-tions is not all that effective so speed is not affected.

MATRIX

General: Keep the boat upright, neutral on the rudder and with as much pressure as possible.

Make sure to have your own reference markings so that with each wind condition you can find immediately the right trim. This is the only way to react quickly and ac-curately to changes in the wind and finding speed will be no surprise but a logical con-sequence.

BftO-1

Shrouds leeward loose

Lower shrouds loose

Genoa halyard little sag

Fairleads above deck

Kicker loose

Traveller to windward, boom midships

Cunningham slight tension

Main foot slight tension

CB max forward, max down

Mastbend prebent, slightly leaning forward

Genoa gap approx 30cm

Genoa clew one

Helmsman forward of fairleads

Crew forward to leeward

Boat heeled to leeward

Bft2-3

Shrouds leeward tight

Lower shrouds tight, mast almost inverted

Genoa halyard tight, no sagging

Fairleads under deck

Kicker tight

Traveller windward

Cunningham loose

Main foot medium

CB 2-3cm aft, max down

Mastbend none, mast vertical

Genoa gap approx 10cm

Genoa clew one

Helmsman on fairlead

Crew forward in trapeze

Boat slight heel to leeward

Bft3-4

Shrouds tight

Lower shrouds tight, keep bottom stiff

Genoa halyard no sagging

Fairleads under deck

Kicker tight

Traveller windward

Cunningham slight tension

Main foot max tension

CB 5-6cm aft, max down

Mastbend keep stiff, some rake

Genoa gap approx 20cm

Genoa clew two

Helmsman just aft of fairlead

Crew just forward of fairlead

Boat slight heel to leeward

Bft4-5

Shrouds tight

Lower shrouds loosen some

Genoa halyard no sagging

Fairleads under deck

Kicker tight

Traveller windward

Cunningham tight

Main foot max tension

CB 15cm aft, approx 10cm up

Mastbend little, some rake

Genoa gap approx 30cm

Genoa clew two – three

Helmsman aft of fairlead

Crew at fairlead

Boat level

Bft5-6

Shrouds max tension

Lower shrouds give a little

Genoa halyard no sagging

Fairleads under deck

Kicker tight (loose reaching)

Traveller windward

Cunningham tight

Main foot max tension

CB 20cm aft, approx 10 cm up

Mastbend reasonable

Genoa gap 40cm

Genoa clew 3

Helmsman aft of fairlead

Crew on or aft of fairlead

Boat level

Bft6-7

Shrouds max tension

Lower shrouds give a little

Genoa halyard give a little

Fairleads under deck

Kicker tight

Traveller windward

Cunningham tight

Main foot tight

CB max aft, top out

Mastbend much

Genoa gap 40-50cm

Genoa clew 3-4

Helmsman aft of fairlead

Crew aft of fairlead

Boat level

Bft7+ (=Get Home!)

Shrouds max tension

Lower shrouds mast just controlable

Genoa halyard give a little

Fairleads under deck

Kicker tight

Traveller windward

Cunningham tight

Main foot tight

CB max aft, top out

Mastbend max

Genoa gap max

Genoa clew 4

Helmsman aft of fairlead

Crew aft of fairlead

Boat level (if possible)